Decrement the rank of an existing member by one. If the member is already at rank zero, then they are removed entirely.
origin
DemoteOrigin
who
Weight: O(1), less if the member's index is highest in its rank.
O(1)
Decrement the rank of an existing member by one. If the member is already at rank zero, then they are removed entirely.
origin: Must be theDemoteOrigin.who: Account of existing member of rank greater than zero.Weight:
O(1), less if the member's index is highest in its rank.